Objectives: The first objective of this grant proposal is to allow the Veterinary Medical Unit (VMU) to more efficiently utilize existing space within the animal facilities. This will allow the VMU to better meet the projected needs of current and future scientists at the Portland VA Medical Center. The second objective of this grant proposal is to protect the health of the animal care and research staff by reducing their exposure to allergens, infectious agents, and injury. The third objective of this grant proposal is to allow the VMU to properly protect all rodents housed in the VMU from potential exposure to pathogens while simultaneously improving animal welfare by improving the microenvironment. Plan/Methods: The first objective will be met through the purchase of ten Maxi-Miser fixed caging systems (Thoren Caging Systems, Inc.). These systems will be placed in five animal housing rooms in the principle animal facility, increasing the effective capacity of these rooms by at least 50%. This expanded capacity will allow opportunities for increased animal housing as populations of mice continue to grow. It will also allow colonies to be consolidated in a caging system that provides superior comfort to the animals, protects the animals from passive pathogen spread (achieving the third objective), and protects the users from exposure to laboratory animal allergens, a leading occupational health hazard in research animal facilities (achieving the second objective). The second and third objectives will also be met through the purchase of 5 workstations, designed for use with filter-topped caging to protect the integrity of the cage microenvironment. We currently have 5 rooms that house rodents in ventilated filter-top caging but do not have access to a workstation.